Putin warns Russia can increase military effort in Syria within 'hours'

President Vladimir Putin on Thursday warned Russia could ramp up its military presence in Syria within "several hours" if needed, as he urged all sides of the conflict to respect a ceasefire.

Putin spoke during a ceremony in the Kremlin's sumptuous St George's Hall to bestow awards on servicemen who fought in Syria, with the military's top brass among some 700 personnel from the armed forces in attendance.

"If there's a need, Russia literally within several hours can ramp up its presence in the region to the size required for the unfolding situation and use the whole arsenal of possibilities we have at our disposal."

"We would not want to do that, a military escalation is not our choice," he added.

"And that's why we put our hopes in the common sense of all parties, in the commitment to the peace process of both the Syrian authorities and the opposition."

On Monday, Putin ordered the surprise withdrawal of most of armed forces from Syria, saying Moscow's task had been "on the whole" completed.

He said Moscow was not abandoning its ally Bashar al-Assad, pledging Russia's continuing military, financial and other support to his regime and praising the Syrian leader.